Rigid recording disk cartridges having a circular, floppy, magnetic or optical disk rotatably mounted within a disk cartridge case are well known. The cartridge is mountable in a disk drive apparatus to rotate and access the recording disk by a magnetic or optical recording head for recording or reproducing information. The cartridge includes a rotatable disk, a cartridge case for housing the disk, and a shutter slidably disposed on a front wall of the case.
Upper and lower walls mate to form the cartridge case. A drive shaft opening is formed through the lower wall to receive a drive shaft to rotate the disk within the cartridge case. A head access opening is formed in the upper and lower walls to access the disk. The head access opening is opened and closed by the shutter which slides between open and closed positions. A spring biases the shutter closed to cover the head access opening.
A press fit assembly boss connects the upper and lower walls of the diskette case, as shown in FIGS. 1 and 2. The assembly boss typically includes a post 138 insertable in a socket 140. The post 138 is a split post design having two halves 138A, 138B. This post 138 flexes at its base which decreases the gap at the top and causes the post to taper upon engagement with the socket 140. This system is susceptible to producing debris during assembly.
This assembly boss is used temporarily during assembly. The permanent assembly is performed by ultrasonic welding of small V-shaped weld beads which are located on or around other bosses in the other corners. Posts and sockets in those corners serve only as the site of the weld beads. The alignment of the shell, both temporarily and permanently, occurs in a press fit boss with the prime reference post. Performance of this assembly boss is affected by its lubricity. The mold used to manufacture a case with this assembly boss must be fabricated by electrical discharge machining. This requires subsequent polishing operations.